J. K. Denny, M. B. Daniel, and F. A. Kovacs, "Computing and
Fitting SSNMR Powder Patterns with the Arithmetic-Geometric Mean and
Edge Detection", Concepts in Magnetic Resonance, 30A(1); 1-20, 2007.
The python program to find chemical shift principal values using the
AGM and
and edge detection heuristic algorithm can be found here.
J. K. Denny and C. K. Trivett, "Cooling the Macon Volunteer
Clinic", The UMAP Journal, 27(4): 431-447, 2006.